I create Excel workbooks on many film composers. Within each, I document the dates of the recording sessions. The only sources of information I have gotten on this frequently elusive data are contained in soundtrack notes and album credits. Apparently, this sort of data comes mainly from the American musicians' unions, who've listed the recording dates along with orchestra personnel on their paperwork records.

I imagine that musicians and conductors arrived at the worksite that morning, just like on any other workday, to do the day's work ahead of them. I'm curious, though, if, on 11/22/63, studios continued the day's work until finished or were the personnel permitted to leave early for the day...

Oh, a professional interest! Why didn't you say so earlier? My apologies.